You don't really have to worry to much about waves with generators, that applies more to battery banks and power inverters. Most inverters generate a modified sine wave which isn't so good for sensitive electronics. As far as generators go, this is one of those times if buying new that you get what you pay for. If you go to harbor freight and buy a Honda knock off from china it WILL FAIL when you need it most and since there's no support or parts you will be out of luck.
Portable or stationary you should have a transfer switch installed if your not going to plug your equipment right into the unit. DO NOT BACK FEED YOUR PANEL THROUGH AN OUTLET. Its a common practice but, even if you flip the main to your house this is a bad idea. Almost all damage I've encountered from genny use was from back feeding improperly.
Bang for the buck a portable is a good choice cheep, easy to service, upgrade, and move. They can run off of diesel, gas, propane, or natural gas. Using one of the later 2 as a fuel will cut down drastically on maintenance, but natural gas reduces the engine horsepower a bit in turn reducing KW output. If you go that route Honda is hands down the way to go. They are super reliable, well supported, light, and quiet. 3 to 5 kw should be fine. Keep in mind that what its rated for is it, if you go over that you'll let the magic smoke out.
Stationary units are the best way to go as far as hands off operation. They are there when you need them whether your home or away. Most run on natural gas right from your meter. They cost a bit more if you buy brand new but it is a piece of mind you'll love to have. As far as brands......Generac if you are someone that has to have new and shinny. In my opinion still junk. If you don't mind buying used then a (pre Cummins buyout) Onan is one of the best generators you'll ever buy. They are under rated bullet proof work horses, and you can pick up a decent 4 to 5 KW for under $500. Most run at 1800 rpm instead of 3600 RPM cutting down on noise and ware, and most are easy to convert to Trifuel if they aren't already. The easiest and most common ones to find are from old motor homes. They convert easily to home/natural gas use and are still widely serviced and supported even back as far as the 1950's. I have used a a 1959 5KW Onan CCK to run my whole house a couple times over the last few years and never had a problem out of it. A few times pulling close to 6200 Watts out of it with out cooking the Generator end (lets see your shinny new Generac do that). Just recently I upgraded to 2 1962 10KW Onan CWs, they are beasts and will prolly keep back up power in the house for my grandkids. If your serious about getting one let me know I'll point you in the right direction.
